Sydney's pollution sparks health warning

A health alert has been issued for some Sydneysiders to avoid outdoor exercise because of high pollution levels.

The Bureau of Meteorology says today's air quality in Sydney is poor.

Children and those with breathing difficulties, such as asthma, are particularly at risk.

Adam Capon from the New South Wales Health Department says air pollution levels will peak at about 7:00pm (AEDT).

"It's particular for this time of year," he said.

"Every summer around this time with the hot, still conditions we generally get these predictions once or twice a year."

Mr Capon says people at risk should reschedule any outdoor exercise.

"It's formed from car exhaust and industrial fumes with the right weather conditions such as today like the still hot conditions, so generally we advise limiting strenuous exercise during the evening," he said.